This invention relates to a method of and apparatus for the heat-treatment of a continuous web, for example for drying a paper web, in which the web is taken through a drying unit with the aid of at least one movable roller and is taken through a drying unit with the aid of at least one movable roller and is constrained to follow a U-shaped path within said drying unit, the web being exposed to drying elements within the drying unit.
It is already known to use infra-red heat for instance, for drying a paper web. According to this previously-known technique infra-red heating elements may be arranged at various positions in, for instance, a paper-making machine, e.g. at the outlet end of such a machine in order to promote final drying and at positions associated with or between rollers at the beginning of the paper machine to promote initial drying. These arrangements have advantages in comparison with conduction or convection drying.